U.S. patent application number 11/843061 was filed with the patent office on 2008-08-14 for method and apparatus for controlling audio signal output level of portable audio device.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Jun-tae Lee.
Application Number | 20080192959 11/843061 |
Document ID | / |
Family ID | 39402689 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080192959 |
Kind Code |
A1 |
Lee; Jun-tae |
August 14, 2008 |
METHOD AND APPARATUS FOR CONTROLLING AUDIO SIGNAL OUTPUT LEVEL OF
PORTABLE AUDIO DEVICE
Abstract
An audio signal output level control method used in an audio
device includes detecting input levels of an audio signal,
determining control modes to be applied to the audio signal based
on the input levels of the audio signal, controlling the input
levels of the audio signal according to the control modes, and
determining output levels corresponding to the controlled input
levels.
Inventors: |
Lee; Jun-tae; (Yongin-si,
KR) |
Correspondence
Address: |
STEIN, MCEWEN & BUI, LLP
1400 EYE STREET, NW, SUITE 300
WASHINGTON
DC
20005
US
|
Assignee: |
Samsung Electronics Co.,
Ltd.
Suwon-si
KR
|
Family ID: |
39402689 |
Appl. No.: |
11/843061 |
Filed: |
August 22, 2007 |
Current U.S.
Class: |
381/107 |
Current CPC
Class: |
H03G 7/002 20130101 |
Class at
Publication: |
381/107 |
International
Class: |
H03G 3/00 20060101
H03G003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2007 |
KR |
2007-15534 |
Claims
1. An audio signal output level control method to be used in an
audio device, comprising: detecting input levels of an audio
signal; determining control modes to be applied to the audio signal
based on the input levels of the audio signal; controlling the
input levels of the audio signal according to the control modes;
and determining output levels corresponding to the input
levels.
2. The method of claim 1, wherein the determining of the control
modes comprises: dividing the audio signal into a plurality of
processing sections based on a predetermined period of time or a
predetermined number of samples; and calculating an average value
of the input levels of the audio signal included in the processing
sections for each of the processing sections, wherein the control
modes to be applied to the audio signal included in each of the
processing sections are determined based on the average values of
the input levels in each of the processing sections.
3. The method of claim 2, wherein the determining of the output
levels comprises: increasing a lowest input level among the input
levels of the audio signal by a predetermined level; determining
the increased input level as a minimum output level; determining a
highest input level among the input levels as a maximum output
level; and determining the output levels between the minimum output
level and the maximum output level using level inclinations
obtained by determining differences between increases in the input
levels and corresponding increases in the output levels.
4. The method of claim 3, wherein the determining of the output
levels further comprises: dividing the input levels into a first
section where the input levels are less than a first threshold, a
second section where the input levels are between the first
threshold and a second threshold, and a third section where the
input levels are more than the second threshold; controlling the
input levels I included in each of the processing sections using
the level inclinations; and determining the output levels based on
the controlled input levels.
5. The method of claim 4, wherein the input levels of the audio
signal included in the second section and the third section are
respectively controlled using two of the level inclinations which
are lower than another of the level inclinations used to control
the input levels of the audio signal included in the first section
and then output as the output levels, based on a first control mode
applied to the audio signal when the average value of the input
levels is less than the first threshold.
6. The method of claim 5, wherein the input levels of the audio
signal included in the third section are controlled using one of
the two level inclinations which is lower than the other of the two
level inclinations used to control the input levels of the audio
signal included in the second section, and then output as the
output levels.
7. The method of claim 4, wherein the input levels of the audio
signal included in the first section and the third section are
respectively controlled using two of the level inclinations which
are lower than another of the level inclinations used to control
the input levels of the audio signal included in the second section
and then output as the output levels, based on a second control
mode applied to the audio signal when the average value of the
input levels is between the first threshold and the second
threshold.
8. The method of claim 4, wherein the input levels of the audio
signal included in the first section and the second section are
respectively controlled using two of the level inclinations which
are lower than another of the level inclinations used to control
the input levels of the audio signal included in the third section
and then output as the output levels, based on a third control mode
applied to the audio signal when the average value of the input
levels is more than the second threshold.
9. The method of claim 8, wherein the input levels of the audio
signal included in the first section are controlled using one of
the two level inclinations which is lower than the other of the two
level inclinations used to control the input levels of the audio
signal included in the second section, and then output as the
output levels.
10. The method of claim 1, wherein the detecting of the input
levels of the audio signal comprises detecting a voltage level
supplied by the audio device, and the determining of the output
levels comprises: increasing the output levels by a predetermined
level based on the detected voltage; and determining the output
levels as final output levels.
11. The method of claim 1, wherein the determining of the output
levels comprises controlling the input levels using a database
which stores the output levels which are determined after the input
levels of the audio signal are controlled according to the control
modes; and determining the output levels based on the stored output
levels.
12. The method of claim 1, wherein the audio device comprises one
of an MP3 player and a cell phone.
13. An audio signal output level control apparatus of an audio
device, comprising: a level detector to detect input levels of an
audio signal; a control mode determiner to determine control modes
to be applied to the audio signal based on the input levels of the
audio signal; and an output level determiner to control the input
levels of the audio signal according to the control modes and to
determine output levels corresponding to the controlled input
levels.
14. The apparatus of claim 13, further comprising: a section
divider to divide the audio signal into a plurality of processing
sections according to a predetermined period of time or a
predetermined number of samples; and an average calculator to
calculate an average value of the input levels of the audio signal
included in each of the processing sections, wherein the control
mode determiner determines the control modes applied to the audio
signal included in each of the processing sections based on the
average values of the input levels in each of the processing
sections.
15. The apparatus of claim 14, wherein the output level determiner
increases a lowest input level among the input levels of the audio
signal by a predetermined level, determines the increased input
level as a minimum output level, determines a highest input level
as a maximum output level, and determines the output levels between
the minimum output level and the maximum output level using level
inclinations corresponding to differences between an increase in
the input levels and a corresponding increase of the output
levels.
16. The apparatus of claim 15, wherein the output level determiner
divides the input levels into a first section where the input
levels are less than a first threshold, a second section where the
input levels are between the first threshold and a second
threshold, and a third section where the input levels are more than
the second threshold, controls the input levels of the audio signal
included in each of the first, second and third sections using the
level inclinations, and determines the output levels based on the
controlled input levels.
17. The apparatus of claim 16, wherein the output level determiner
respectively controls the input levels of the audio signal included
in the second section and the third section using two of the level
inclinations which are lower than another of the level inclinations
used to control the input levels of the audio signal included in
the first section and determines the controlled input levels as the
output levels, based on a first control mode applied to the audio
signal when the average value of the input levels is less than the
first threshold.
18. The apparatus of claim 17, wherein the output level determiner
controls the input levels of the audio signal included in the third
section using one of the two level inclinations which is lower than
the other of the two level inclinations used to control the input
levels of the audio signal included in the second section and
determines the controlled input levels as the output levels.
19. The apparatus of claim 16, wherein the output level determiner
respectively controls the input levels of the audio signal included
in the first section and the third section using two of the level
inclinations which are lower than another of the level inclinations
used to control the input levels of the audio signal included in
the second section and determines the controlled input levels as
the output levels, based on a second control mode applied to the
audio signal when the average value of the input levels is between
the first threshold and the second threshold.
20. The apparatus of claim 16, wherein the output level determiner
respectively controls the input levels of the audio signal included
in the first section and the second section using two of the level
inclinations which are lower than another of the level inclinations
used to control the input levels of the audio signal included in
the third section and determines the controlled input levels as the
output levels, based on a third control mode applied to the audio
signal when the average value of the input levels is more than the
second threshold.
21. The apparatus of claim 20, wherein the output level determiner
controls the input levels of the audio signal included in the first
section using one of the two level inclinations which is lower than
the other of the two level inclinations used to control the input
levels of the audio signal included in the second section, and
determines the controlled input levels as the output levels.
22. The apparatus of claim 15, wherein the level detector detects
the input levels of the audio signal and a level of voltage
supplied by the audio device, and the output level determiner
increases the output levels by a predetermined level based on the
detected level of voltage, and determines the output levels as
final output levels.
23. The apparatus of claim 13, wherein the output level determiner
controls the input levels using a database which stores the output
levels determined after the input levels of the audio signal are
controlled according to the control modes and determines the output
levels based on the stored output levels.
24. The apparatus of claim 13, wherein the audio device comprises
one of an MP3 player and a cell phone.
25. A computer readable recording medium encoded with a computer
readable program with processing instructions for executing the
method of claim 1.
26. A method to control a signal output, comprising: calculating an
average intensity of detected input levels of a signal; applying a
control mode to the detected input levels based on the calculated
average; and outputting output levels based on the controlled input
levels.
27. The method of claim 26, wherein the signal comprises an audio
signal.
28. The method of claim 26, wherein the applying of the control
mode comprises: setting a plurality of thresholds which are
different from each other in regard to signal intensity of the
signal; and determining the control mode to apply to the input
levels based on a location of the calculated average in comparison
to the plurality of thresholds.
29. The method of claim 28, wherein the plurality of thresholds
define sections, and the applying of the control mode further
comprises: applying level inclinations to the input levels based on
locations of the input levels in comparison to the sections,
wherein the level inclination is used to increase the output levels
in relation to the corresponding input levels, and the level
inclination applied to the input levels in the section having the
calculated average has the highest inclination in comparison to the
level inclinations applied to the input levels in the other
sections.
30. The method of claim 29, wherein the outputting of the output
levels comprises: increasing a lowest input level among the input
levels by a predetermined level; setting the increased input level
as a minimum output level; and outputting the output levels by
increasing each of the input levels from the minimum output level
by an amount of the corresponding level inclinations.
31. The method of claim 30, further comprising detecting a voltage
level supplied by a device supplying the signal, wherein the
outputting of the output levels comprises increasing the output
levels by a predetermined level based on the detected voltage.
32. The method of claim 31, wherein the device comprises one of an
MP3 player and a cell phone.
33. An apparatus to control a signal output, comprising: an average
calculator to calculate an average intensity of detected input
levels of a signal; a control mode determiner to apply a control
mode to the detected input levels based on the calculated average;
and an output level determiner to control the input levels of the
audio signal according to the applied control mode and to determine
output levels corresponding to the controlled input levels.
34. The apparatus of claim 33, wherein the signal comprises an
audio signal.
35. The apparatus of claim 33, wherein the control mode determiner
applies the control mode by setting a plurality of thresholds which
are different from each other in regard to signal intensity of the
signal, and determines the control mode to apply to the input
levels based on a location of the calculated average in comparison
to the plurality of thresholds.
36. The apparatus of claim 35, wherein the plurality of thresholds
define sections, and the output level determiner applies level
inclinations to the input levels based on locations of the input
levels in comparison to the sections, wherein the level inclination
is used to increase the output levels in relation to the
corresponding input levels, and the level inclination applied to
the input levels in the section having the calculated average has
the highest inclination in comparison to the level inclinations
applied to the input levels in the other sections.
37. The apparatus of claim 36, wherein the output level determiner
increases a lowest input level among the input levels by a
predetermined level, sets the increased input level as a minimum
output level, and outputs the output levels by increasing each of
the input levels from the minimum output level by an amount of the
corresponding level inclinations.
38. The apparatus of claim 37, further comprising a level detector
to detect the input levels, wherein the level detector detects a
voltage level supplied by a device supplying the signal, and the
outputting of the output levels comprises increasing the output
levels by a predetermined level based on the detected voltage.
39. The apparatus of claim 38, wherein the device comprises one an
MP3 player and a cell phone.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Korean Application
No. 2007-15534, filed Feb. 14, 2007 in the Korean Intellectual
Property Office, the disclosure of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Aspects of the present invention relate to a method and
apparatus to control an audio signal output level, and more
particularly, to a method and apparatus to control an audio signal
output level of a portable audio device.
[0004] 2. Description of the Related Art
[0005] People frequently listen to music using various types of
audio devices. In particular, portable audio reproducing devices,
such as MP3 players, mobile phones having a music reproduction
function, etc., which store hundreds to thousands of music tracks,
have recently become popular. As a result, many people are
listening to music using such portable audio reproducing
devices.
[0006] Music stored in portable audio reproducing devices does not
have the same level as recorded audio signals. Specifically, some
music files can include high level audio signals, and other music
files can include low level audio signals. Music including the high
level audio signals produce loud sound, and music including the low
level audio signals produce soft sound. In this regard, music
including extremely low level audio signals does not produce a
sufficient volume of sound even if the volume is turned up. This
insufficient volume degrades the listening environment.
[0007] Portable audio reproducing devices have embedded batteries
to supply voltage for portable terminals. As time elapses, the
battery voltage for portable terminals is reduced. As the voltage
supplied by the battery decreases, the volume level of the audio
signal decreases. As a result, reproduced music sound becomes
softer, resulting in a poor listening environment. Conventionally,
when a low volume level audio signal is input or a battery supplies
a lower voltage to a portable terminal, a reproduced music sound
becomes softer, creating a poor listening environment.
SUMMARY OF THE INVENTION
[0008] Aspects of the present invention provide an audio signal
output level control method and apparatus for a portable audio
device so that an audio signal input with a low volume level or an
audio signal output with a low volume level due to a limited
voltage level is output with a high volume level.
[0009] An aspect of the present invention provides an audio signal
output level control method to be used in an audio device,
including detecting input levels of an audio signal, determining
control modes to be applied to the audio signal based on the input
levels of the audio signal, controlling the input levels of the
audio signal according to the control modes, and determining output
levels corresponding to the input levels.
[0010] According to an aspect, the method further includes dividing
the audio signal into a plurality of processing sections based on a
predetermined period of time or a predetermined number of samples,
and calculating an average value of the input levels of the audio
signal included in the processing sections for each of the
processing sections, wherein the control modes to be applied to the
audio signal included in each of the processing sections are
determined based on the average values of the input levels in each
of the processing sections.
[0011] According to an aspect, the determining of the output levels
includes increasing a lowest input level among the input levels of
the audio signal by a predetermined level, determining the
increased input level as a minimum output level, determining a
highest input level among the input levels as a maximum output
level, and determining the output levels between the minimum output
level and the maximum output level using level inclinations
obtained by determining the differences between increases in the
input levels and corresponding increases in the output levels.
[0012] According to an aspect, the determining of the output levels
further includes dividing the input levels into a first section
where the input levels are less than a first threshold, a second
section where the input levels are between the first threshold and
a second threshold, and a third section where the input levels are
more than the second threshold; controlling the input levels
included in each of the processing sections using the different
level inclinations, and determining the output levels based on the
controlled input levels.
[0013] According to an aspect, the input levels of the audio signal
included in the second and third sections are respectively
controlled using a level inclination which is lower than another
level inclination used to control the input levels of the audio
signal included in the first section and then output as the output
levels, based on a first control mode applied to the audio signal
when the average value of the input levels is less than the first
threshold.
[0014] According to an aspect, the input levels of the audio signal
included in the third section are controlled using one of the two
level inclinations which is lower than the other of the two level
inclinations used to control the input levels of the audio signal
included in the second section, and then output as the output
levels.
[0015] According to an aspect, the input levels of the audio signal
included in the first and third sections are respectively
controlled using two of the level inclinations which are lower than
another of the level inclinations used to control the input levels
of the audio signal included in the second section and then output
as the output levels, based on a second control mode applied to the
audio signal when the average value of the input levels is between
the first threshold and the second threshold.
[0016] According to an aspect, the input levels of the audio signal
included in the first and second sections are respectively
controlled using a level inclination which is lower than another of
the level inclinations which is used to control the input levels of
the audio signal included in the third section and then output as
the output levels, based on a third control mode applied to the
audio signal when the average value of the input levels is more
than the second threshold.
[0017] According to an aspect, the input levels of the audio signal
included in the first section are controlled using one of the two
level inclinations which is lower than the other of the two level
inclinations used to control the input levels of the audio signal
included in the second section and the output as the output
levels.
[0018] According to an aspect, the detecting of the input levels of
the audio signal includes detecting a level of a voltage supplied
by the audio device, and the determining of the output levels
further includes increasing the output levels by a predetermined
level based on the detected voltage, and determining the output
levels as final output levels.
[0019] According to an aspect, the determining of the output levels
further includes controlling the input levels using a database
which stores the output levels which are determined after the input
levels of the audio signal are controlled according to the control
modes and determining the output levels based on the stored output
levels.
[0020] Another aspect of the present invention provides an audio
signal output level control apparatus of a portable audio device,
including a level detector to detect input levels of an audio
signal, a control mode determiner to determine control modes to be
applied to the audio signal based on the input levels of the audio
signal, and an output level determiner to control the input levels
of the audio signal according to the control modes and to determine
output levels corresponding to the controlled input levels.
[0021] According to another aspect, the apparatus further includes
a section divider to divide the audio signal into a plurality of
processing sections according to a predetermined period of time or
a predetermined number of samples, and an average calculator to
calculate an average value of the input levels of the audio signal
included in each of the processing sections, wherein the control
mode determiner determines the control modes applied to the audio
signal included in each of the processing sections based on the
average values of the input levels in each of the processing
sections.
[0022] Yet another aspect of the present invention provides a
computer readable recording medium encoded with a computer readable
program with processing instructions for executing an audio signal
output level control method to be used in an audio device, the
method including detecting input levels of an audio signal,
determining control modes to be applied to the audio signal based
on the input levels of the audio signal, controlling the input
levels of the audio signal according to the control modes and
determining output levels corresponding to the input levels.
[0023] Additional aspects and/or advantages of the invention will
be set forth in part in the description which follows and, in part,
will be obvious from the description, or may be learned by practice
of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] These and/or other aspects and advantages of the invention
will become apparent and more readily appreciated from the
following description of the embodiments, taken in conjunction with
the accompanying drawings of which:
[0025] FIG. 1 is a block diagram of an audio signal output level
control apparatus of a portable audio device according to an
embodiment of the present invention;
[0026] FIG. 2 is a graph illustrating the operation of a section
separator illustrated in FIG. 1;
[0027] FIG. 3 is a graph illustrating sections of input levels to
control the input levels according to an embodiment of the present
invention;
[0028] FIG. 4 is a graph illustrating a first control mode
according to an embodiment of the present invention;
[0029] FIG. 5 is a flowchart illustrating the operation of an
output level determiner according to an embodiment of the present
invention;
[0030] FIG. 6 is a graph illustrating a second control mode
according to an embodiment of the present invention;
[0031] FIG. 7 is a graph illustrating a third control mode
according to an embodiment of the present invention; and
[0032] FIG. 8 is a flowchart illustrating an audio signal output
level control method used in a portable audio device according to
an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0033] Reference will now be made in detail to the present
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to the like elements throughout. The embodiments are
described below in order to explain the present invention by
referring to the figures.
[0034] FIG. 1 is a block diagram of an audio signal output level
control apparatus 10 to be used with a portable audio device
according to an embodiment of the present invention. Referring to
FIG. 1, the audio signal output level control device 10 to be used
with the portable audio device includes a level detector 110, a
section divider 120, an average calculator 130, a control mode
determiner 140, and an output level determiner 150. It is
understood that the audio signal output level control apparatus 10
is not limited to being used in a portable audio device, and may
instead be used in non-portable or semi-portable audio devices as
well, such as mini-stereos, etc.
[0035] The level detector 110 detects an input level of an audio
signal. The audio signal can be a digital or analog signal. The
level detector 110 also detects the level of a voltage supplied by
the audio device (not shown). When the level detector 110 detects
the level of the voltage, the output level determiner 150 can
determine an output level.
[0036] The section divider 120 divides the audio signal into a
plurality of processing sections according to a predetermined
period of time, a predetermined number of samples, or according to
some other criteria. It is understood that the section divider 120
can divide the audio signal according to many different types of
criteria, such as by tracks, by groups of tracks, by seconds, by
minutes, etc.
[0037] FIG. 2 is a graph illustrating an operation of the section
divider 120 illustrated in FIG. 1. Referring to FIG. 2, when the
audio signal is an analog signal 210, the section divider 120
divides the analog signal 210 into t.sub.1 and t.sub.2 according to
a predetermined period of time. When the audio signal is a digital
signal 220, the section divider 120 divides the digital signal 220
into s.sub.1 and s.sub.2 according to a predetermined number of
samples. According to an aspect of the present invention, the
predetermined period of time used to divide the audio signal 210 is
0.01 seconds, and the predetermined number of samples used to
divide the digital signal 220 is 440. However, it is understood
that the predetermined period of time can be more or less than 0.01
seconds and is not limited to being one time period, and that the
predetermined number of samples can be more or less than 440 and is
not limited to being one number.
[0038] The section divider 220 divides the audio signal 210 into
smaller processing sections because the operation of outputting a
larger audio signal which is completely processed, i.e., an
undivided audio signal 210, takes a long time to output. For
example, if the audio signal 210 is processed as a whole, it is
possible to output the completely processed audio signal 210.
However, if another audio signal is previously input, the audio
signal 210 can be completely processed only after the previously
input audio signal is completely processed. However, the section
divider 220 is not required in all aspects of the present
invention.
[0039] The average calculator 130 calculates an average value of
input levels included in the processing sections of the audio
signal 210 divided by the section divider 120. Alternatively, if
the section divider 120 is not used, the average calculator 130
calculates an average value of input levels of the whole audio
signal 210 if the audio signal 210 is not divided into sections.
Otherwise, the average calculator 130 calculates individual
averages of the processing sections.
[0040] The control mode determiner 140 determines a control mode to
be applied to the audio signal 120 based on an input level of the
audio signal 210 determined by the level detector 110. The control
mode determiner 140 determines the control mode to be applied to
the audio signal 210 based on the whole audio signal 210 if the
audio signal is not divided into processing sections or the average
value of the input levels of the audio signal 210 included in the
processing sections if the audio signal 210 is divided into
processing sections. More specifically, the control mode determiner
140 selects different control modes when the average value of the
input levels of the audio signal 210 is less than a first
threshold, is between the first threshold and a second threshold,
and is greater than the second threshold, i.e., if a recording
level of the audio signal 210 is low, middle, and high in regard to
signal intensity. It is understood that the control mode determiner
140 can set one or more than two thresholds.
[0041] When the recording level of the audio signal 210 is low, the
control mode determiner 130 applies a first control mode to the
audio signal 210. If the recording level of the audio signal 210 is
at a middle level, the control mode determiner 130 applies a second
control mode to the audio signal 210. If the recording level of the
audio signal 210 is high, the control mode determiner 130 applies a
third mode to the audio signal. It is understood that the control
mode determiner 140 is not limited to applying control modes based
on three levels, and may instead apply control modes based on more
or less than three levels.
[0042] Level inclinations used to control the input levels vary
according to each control mode. Each level inclination corresponds
to an increase of each output level according to an increase of
each input level. The level inclinations, the first control mode,
the second control mode, and the third control mode will be
described in detail with reference to the output level determiner
150. Each control mode is divided into sections according to the
input levels of the audio signal 210 and is designed to control the
input levels using the different level inclinations corresponding
to the sections. The sections which are created according to the
input levels (FIG. 3) are not the same as the processing sections
(FIG. 2).
[0043] FIG. 3 is a graph illustrating sections of the input levels
to control the input levels according to an embodiment of the
present invention. Referring to FIG. 3, an x-axis indicates time,
and a y-axis indicates low and high levels of the audio signal 210.
The audio signal 210 is divided into sections up to on the time
axis.
[0044] The input levels of the audio signal 210 are divided into a
first section 300, a second section 302, and a third section 304
based on a first dB threshold and a second dB threshold during a
first processing section from 0 to t1 (FIG. 2). For example, the
first threshold and the second threshold can be respectively set to
-60 db and -30 db. However, aspects of the present invention are
not limited thereto. Furthermore, it is understood that the graph
shown in FIG. 3 is only one example of an audio analog signal, and
that many other waveforms may instead be used according to other
aspects of the present invention.
[0045] The first section 300 includes the audio signal 210 having a
low input level. The second section 302 includes the audio signal
210 having a middle input level. The third section 304 includes the
audio signal 210 having a high input level.
[0046] The input levels of the audio signal 210 included in the
first through third sections 300, 302, and 304 are controlled using
different level inclinations, so that the audio signal is divided
into the sections 300, 302, and 304 according to the input levels.
The output level determiner 150 controls the input levels of the
audio signal 210 according to the control mode determined by the
control mode determiner 140 and determines the output level of the
audio signal based on the input levels.
[0047] FIG. 4 is a graph illustrating the first control mode
according to an embodiment of the present invention. Referring to
FIG. 4, input levels and corresponding output levels are
illustrated in the first control mode. As noted above, the control
mode determiner 130 applies the first control mode when an average
value of the input levels is less than the first threshold.
[0048] At a line 410, the input levels are output as corresponding
output levels without being controlled by the control mode
determiner 140. For example, if an input level is -60 db, a
corresponding output level is also -60 db at the line 410. The
input level and the corresponding output level have the same
dynamic range between 0 db and -100 db.
[0049] In contrast to the line 410, at the lines 420, 430, and 440,
the control mode determiner 140 controls the input levels and the
output level determiner 150 determines the corresponding output
levels based on the controlled input levels. The input levels are
divided into the first, second, and third sections, 300, 302, and
304, and level inclinations differ from each other in the three
sections 300, 302, and 304. The graphs 420, 430, and 440 show a
high level, a middle level, and a low level of voltage supplied by
the audio device, respectively. Line 420 will be representatively
described to describe each of lines 420, 430, and 440.
[0050] At the line 420, two level inclinations which are lower than
another level inclination used to control the input level of the
audio signal 210 included in the first section 300 are used to
control the input levels of the audio signal 210 included in the
second and third sections and to determine the corresponding output
levels. In other words, in the first control mode, the level
inclination of the line 420 applied in the first section 300 has a
higher slope than the level inclinations of the line 420 applied in
the second section 302 and the third section 304, as shown in FIG.
4.
[0051] The input level of the audio signal 210 included in the
first section 300 is controlled using a relatively high level
inclination since a recording level of the audio signal 210 is low
in the first control mode, the first section assumed to have many
audio signals 210. If a very low level inclination was applied to
the first section 300, the very low level inclination would greatly
reduce a dynamic range of output levels of audio signals 210, which
would cause damage to the quality of the audio signal 210.
Accordingly, a relatively high level inclination is used.
[0052] The operation of the output level determiner 150 to obtain
the output level as illustrated by the line 420 of FIG. 4 will now
be described with reference to FIG. 5. FIG. 5 is a flowchart
illustrating the operation of the output level determiner 150
according to an embodiment of the present invention. Referring to
FIG. 5, at operation 510, the output level determiner 150 increases
a lowest level among input levels of the audio signal 210 by a
predetermined level and determines the lowest level to be a minimum
output level.
[0053] At the line 420, the output level determiner 150 increases
an input level of -100 db by 36 db and determines, or sets, the
increased input level as the minimum output level. At operation
520, the output level determiner 150 determines, or sets, a highest
level among the input levels of the audio signal 210 as a maximum
output level. At the line 420, the output level determiner 150
determines the highest level of 0 db as the maximum output
level.
[0054] At operation 530, the output level determiner 150 divides
the input levels into the first, second, and third sections 300,
302, and 304. As shown in FIG. 4, at the line 420, the output level
determiner 150 divides the input levels into the first, second, and
third sections 300, 302, and 304. However, aspects of the present
invention are not limited thereto, and the output level determiner
150 can divide the input levels into more or less than three
sections.
[0055] At operation 540, the output level determiner 150 controls
the input levels of the audio signal 210 in the three sections 300,
302, and 304 which have different level inclinations from each
other, and determines corresponding output levels between the
minimum output level and the maximum output level. At the line 420,
as described above, the output level determiner 150 controls the
input levels of the audio signal 210 included in the second and
third sections 302 and 304 using a level inclination that is lower
than another level inclination used to control the input level of
the audio signal 210 included in the first section 300, and
determines the corresponding output levels based on the level
inclinations.
[0056] The corresponding output levels at the line 420 become
higher than output levels that are determined after input levels
which are not controlled, i.e., input levels at the line 410. For
example, at the line 420, if an input level is -60 db, the
corresponding output level is determined to be -45 db. However, as
illustrated in FIG. 4, a dynamic range of 100 db of the output
levels that are determined after the input levels are not
controlled at the line 410 is broader than the dynamic range of 60
db of the output level determined after the input levels are
controlled at the line 420.
[0057] The second and third sections 302 and 304 can have the same
level inclinations. Alternatively, the input levels of the audio
signal 210 included in the third section 304 can be controlled and
then output as the corresponding output levels using a level
inclination which is lower than the level inclination of the second
section 302. Moreover, the input level of the audio signal 210
included in the third section 304 can be controlled and then output
as the corresponding output level using a level inclination which
is higher than the level inclination of the second section 302.
[0058] At lines 430 and 440, the output levels are controlled and
determined as final output levels based on the level of voltage
supplied by the audio device and detected by the level detector
110. The graphs 420, 430, and 440 represent a high level, a middle
level, and a low level of voltage supplied by the audio device,
respectively. The output levels increase by a predetermined level
in order to increase the output levels to compensate for the
reduction of the audio signal caused by a decrease in a voltage
level supplied by the audio device, for example, when a battery
gets low.
[0059] For example, the output level determiner 150 increases the
output levels determined according to the line 420 by the
predetermined level, and determines, or sets, the increased output
levels as the final output levels 430 and 440 when the voltage
drops from a high level to a middle level and a low level,
respectively. Although the minimum output levels increase by 2 db
or 4 db, the output levels of the audio signal 210 do not uniformly
increase by 2 db or 4 db, but differ from each other according to
the three sections 300, 302, and 304.
[0060] FIG. 6 is a graph illustrating the second control mode
according to an embodiment of the present invention. Referring to
FIG. 6, input levels and corresponding output levels are
illustrated in the second control mode. The control mode determiner
applies the second control mode to the audio signal 210 when an
average value of the input levels is determined to be between the
first threshold and the second threshold.
[0061] The output level determiner 150 controls the input levels of
the audio signal 210 included in the first and third sections 600
and 604 using two level inclinations which are lower than another
level inclination used in the second section 602 and determines the
corresponding output levels in the second control mode. Since the
majority of the audio signal is included in the second section when
the second control mode is used, a low level inclination of the
second section 602 reduces a dynamic range of the audio signal 210
included in the second section 210, which causes damage to the
quality of the audio signal 210. Accordingly, a relatively high
level inclination is used in the second section 602. Furthermore,
the level inclinations used in the first section 600 and the third
section 604 may be equal to each other, or one may be higher than
the other.
[0062] Lines 610, 620, and 630 correspond to lines 420, 430, and
440 shown in FIG. 4, and other descriptions are the same as the
description of the first control mode described above with
reference to FIG. 4. Thus, descriptions thereof are not
repeated.
[0063] FIG. 7 is a graph illustrating the third control mode
according to an embodiment of the present invention. Referring to
FIG. 7, input levels and corresponding output levels are
illustrated in the third control mode. The control mode determiner
130 applies the third control mode when an average value of the
input levels of the audio signal 210 is more than the second
threshold.
[0064] The output level determiner 150 controls the input levels of
the audio signal 210 included in the first and second sections 700
and 702 using two level inclinations which are lower than another
level inclination used in the third section 704 and determines the
corresponding output levels in. Since the majority of the audio
signal 210 is included in the third section 704, a low level
inclination of the third section 704 reduces a dynamic range of the
audio signal 210 in the third section 704, which causes damage to
the quality of the audio signal 210. Accordingly, a high level
inclination is applied to the third section 704.
[0065] The first and second sections 700 and 702 shown in FIG. 7
can have the same level inclinations. Alternatively, as shown in
FIG. 7, the input levels of the audio signal included in the first
section 700 can be controlled and determined as the corresponding
output levels using a level inclination which is lower than a level
inclination of the second section 702. Moreover, the level
inclination in the first section 700 may be higher than the level
inclination of the second section 702.
[0066] Lines 710, 720 and 730 correspond to lines 410, 420, and 430
shown in FIG. 4, and other descriptions of the third control mode
are the same as the description of the first control mode described
above with reference to FIG. 4. Thus, descriptions thereof are not
repeated.
[0067] Meanwhile, the output level determiner 150 controls the
input levels based on a database (not shown) which stores the
output levels that are determined after the input levels of the
audio signal 210 are controlled according to the control modes, and
determines the output levels based on the stored input levels. In
more detail, the optimum output levels are calculated by conducting
a test or the like and are stored in the database. If the control
modes are determined according to the input levels of the audio
signal 210, the output level determiner 150 controls the input
levels based on the output levels stored in the database so that
the audio device outputs the audio signal 210 having the stored
output levels.
[0068] FIG. 8 is a flowchart illustrating an audio signal output
level control method used in an audio device according to an
embodiment of the present invention. Referring to FIG. 8, at
operation 810, the input levels of the audio signal 210 are
detected. At this time, the level detector 110 detects a level of
voltage supplied by the audio device. While the audio device may be
portable, it is understood that aspects of the present invention
may also be applied to non-portable audio devices as well.
[0069] At operation 820, control modes applied to the audio signal
210 are determined based on the input levels of the audio signal.
When the audio signal 210 is divided into a plurality of sections,
such as the first, second, and third sections 300, 302, and 304
(FIG. 3) according to a predetermined period of time or a
predetermined number of samples, different control modes are
applied to the audio signal according to the sections.
[0070] At operation 830, the input levels of the audio signal 210
are controlled and corresponding output levels are determined based
on the control modes. The output levels that are determined after
the input levels are controlled are higher than those determined
after the input levels are not controlled, but have a dynamic range
which is narrower than that of the output levels which are not
controlled. Therefore, in order to compensate for the narrow
dynamic range of the output levels determined after the input
levels are controlled, level inclinations to control the input
levels vary according to the sections of the input levels based on
the control modes. For example, as shown in FIG. 4, since the first
control mode is used when the average input level of the audio
signal 210 is at a low level, the majority of the audio signal 210
is at a low level, and the first section 300 is set to have the
highest level inclination to supply the greatest boost to the
portion of the audio signal 210 in the first section 300, thereby
increasing the output level of the majority of the audio signal
210.
[0071] Aspects of the present invention may be embodied on a
computer-readable recording medium encoded with a computer readable
program with processing instructions. Computer-readable recording
media include many kinds of recording device that store computer
system-readable data. ROM, RAM, CD-ROM, magnetic tape, floppy disc,
optical data storage, etc. are used as computer-readable recording
media. The computer-readable recording media can also be realized
in the form of a carrier wave (e.g., transmission through the
Internet).
[0072] Aspects of the present invention detect input levels of an
audio signal 210, determine control modes applied to the audio
signal 210 based on the input levels of the audio signal 210,
control the input levels of the audio signal 210 according to the
control modes, and determine output levels corresponding to the
input levels. In doing so, aspects of the present invention provide
an apparatus and method to output an audio signal 210 that is input
at a low volume level, and/or an audio signal 210 that is to be
output at a low level due to a limited battery voltage level, at a
high level. Additionally, aspects of the present invention are not
limited to audio signals 210, but may also be applied to other
types of signals, such as video signals or data transmission
signals of various types. For example, an aspect of the present
invention may be implemented to boost a brightness of a video
signal using the same methods as described above with reference to
the audio signal 210.
[0073] Although a few embodiments of the present invention have
been shown and described, it would be appreciated by those skilled
in the art that changes may be made in this embodiment without
departing from the principles and spirit of the invention, the
scope of which is defined in the claims and their equivalents.
* * * * *